As a syringe for administering a small amount of drug such as a protein preparation, an antibody preparation, a hyaluronic acid, and insulin, such a syringe can include a thin diameter puncture needle that is fixed to a distal end part of an outer cylinder. In many cases, a high-viscosity drug is used as a drug. When such a high-viscosity drug is administered, an administering operation might not be easy, since a small diameter puncture needle has high flow resistance. Although silicone oil is sometimes applied to an inner surface of an outer cylinder as a sliding property, such a lubricant might cause aggregation or denaturation of a drug due to an interaction with a placed drug.
Therefore, a lubricant is preferably not used in a syringe. However, since a sliding property in an outer cylinder of a gasket can be deteriorated in such a syringe, an administering operation becomes difficult. Furthermore, by having such a sliding property, a risk of occurrence of a secondary medical accident is increased due to a syringe that is broken at the time of administration. Therefore, a means to lower a sliding resistance value without using a lubricant is desired in consideration of drug stability and safety during administration.
In this context, a gasket has been proposed in WO 2009/084646 A1 by the present applicant. The present applicant has also proposed JP 2004-041391 A.
The gasket of WO 2009/084646 A1 has a relatively good sliding property. Owing to an injection needle of JP 2004-041391 A, an injection can be performed without hurting or damaging a patient, and further without causing a patient to feel fearful or anxious. The injection needle of JP 2004-041391 A is relatively suitable since it can reduce channel resistance of the entire injection needle when a drug solution is injected into a living body.
As a syringe with needle, however, a syringe with needle capable of administering a drug solution having a higher concentration at low injection resistance and with low gasket pressing force is required.